There have been proposed various methods for forming a color filter for a display element. Among them, a method using electrodeposition has become noteworthy.
For example, Japanese Kokai Publication 61-272720 discloses a method wherein a positive type photosensitive resin layer is formed on an electroconductive layer which is formed on a substrate, and then is exposed and developed, followed by forming color layers by electrodeposition. This method utilizes such properties that the positive type photosensitive layer is changed to be soluble with a developer only at the portion which has been exposed to light, and the non-exposed portion remains photosensitive. After developing the exposed portion, a color layer is formed on a bared electroconductive layer by electrodeposition. Then, the non-exposed portion of the positive type photosensitive layer is exposed to light and the same operations are effected. This process is ideally possible from an ideal standpoint, but in actuality is almost impossible. The positive type photosensitive resin composition which is commercially available generally contains quinonediazide and is chemically modified once contacted with a developer. The modified photosensitive resin composition loses its photosensitivity and can not be exposed and developed any more. Therefore, in actuality, the photosensitive resin layer once contacted with the developer is removed and then a new positive type photosensitive resin composition is newly applied thereto. These removal and application processes make the process complicated.
Japanese Kokai Publication 1-152449 discloses that a color negative type photosensitive resin composition is spin-coated on a substrate and then exposed and developed to form a patterned color layer, and the same process is conducted with a negative type photosensitive resin composition having another color. In this method, spin-coating is essential but is difficult to apply to a substrate having a large area. Also, since the color negative type photosensitive resin composition is spin-coated on an already formed different color layer, a difference in level and color shade tend to occur.